Medical professionals frequently face unmet information needs during their daily routines. We investigated the use of web search engines through a large-scale survey including 500 European physicians, as well as local user testing that observed the search behavior of physicians when facing clinical questions. We identified several differences in the search requirements and behaviors of different groups of physicians based on level of qualification and level of specialization. We also found user testing a valuable source of information about the search preferences of medical professional. The survey and user tests we conducted are among the largest and most detailed that have been conducted in this domain.